The present invention is directed to a system and method for isolating the shuttle area of a press during a die change operation. More particularly, the present invention is directed to a system and method for isolating the shuttle area existing between tandem presses so that an operator can safely work in the shuttle area during an ongoing die change.
Presses and die sets are commonly used in various manufacturing processes to form, trim, or pierce components, typically metal components. For example, die sets may be used to blank, form and trim numerous automotive components, which are subsequently assembled into an automobile. Depending on the particular component to be formed or altered, a single die and press may be employed, or several related dies located in a series of presses may be used.
The use of multiple dies in multiple presses is generally required when forming components with complex geometries. Such a process is often referred to as a tandem press operation, because the presses associated therewith are typically arranged in tandem such that the exit side of one press can feed the entry side of a subsequent, adjacent press. Thus, a tandem press line is formed. Such a process is often also referred to as a progressive die (prog-die) operation, because the component of interest is progressively created as it passes from the first die to the last die.
In a tandem press line, the space between adjacent presses is typically used as a shuttle area. More specifically, this space is usually occupied by component transfer equipment such as shuttle tables and/or part handlers that function to transfer the in-process component from one die to the next. For example a part unloader may be provided to remove a part from a first die and load the part onto a shuttle table. The shuttle table then advances toward the next press, where a part loader removes the component and places it on the die located therein. There may be several individual sets of component transfer equipment, depending on how many presses are used in the process.
It is also common for such tandem press operations to produce a plurality of different components. For example, a tandem press line in an automobile manufacturing facility may be used to produce hoods, trunks, fenders, door skins, and various other body components. In addition to the various dissimilar body components that may be produced by such a tandem press operation, it is also common to produce such components for more than one vehicle. Thus, as can be understood, such a tandem press line will typically have a multitude of different dies associated therewith.
When switching the manufacturing operation from one component to another, it is typically required to replace the die in each press. To this end, most tandem press lines employ some type of die change system, whereby current dies can be removed from each press and new dies installed thereto. Preferably, tandem press lines employ automatic die change systems, such as systems wherein the dies are moved into and out of the presses on rolling bolsters. During an automatic die change, the dies to be replaced are released by the clamping devices of their respective presses. Since these dies are also affixed to sliding bolsters, the new dies can be moved into the presses while the old dies are simultaneously moved out.
Just as the process of manufacturing dissimilar components requires the use of different dies, it also normally requires the use of different component transfer equipment. Consequently, in conjunction with a die change, it is typically necessary to also change part handler arms, shuttle table jigs, and/or other similar items. This process must normally be performed after the die change process has been completed, as it would be unsafe to allow workers into the press area while the dies and bolsters are moving into position.
Because the dies that are used in such tandem press operations can be quite large, it generally takes several minutes to complete a die change even if an automatic die change system is used. To this die change time must then be added the time required to convert the associated component transfer equipment; which generally must be accomplished by hand. As such, an overall changeover of the tandem press line can frequently take approximately five minutes or more, even with multiple workers assigned to the task.
As can be appreciated, especially with respect to a high volume manufacturing operation, lost production time generally equates to lost profits. Initially, five minutes of downtime may not seen significant. However, when it is realized that several changeovers may be required per shift of a multiple-shift manufacturing operation, and that such an operation may run hundreds of days per year, it can be understood that the accumulated downtime may be significant. For example, a tandem press line running three shifts per day, 260 days per year, with on average three, five minute changeovers per shift, will have a total yearly downtime of approximately 11,700 minutes, or 195 hours—not insignificant by any means.